I was told that the 6 bolt case I have will not be good for a perfomance rebuild . Do I need to go find a 8 bolt case now ? The trans I have now has HD 46 cast into the bellhousing and the front pump has the 895 on it.

We have not found any significant power limitations (within reason) to the 6-bolt TH400 transmission case. We have a customer with a 3,000 pound drag radial car equipped with an alcohol EFI 632 and an F-3R 136 ProCharger utilizing a 6-bolt TH400 case without any issues. Another customer of ours runs a 6-bolt case behind his 498 DRCE II combination that turns upwards of 10,200 RPM, and, again, has had no issues.

We do prefer to use an 8-bolt case when we're building a unit for use with a JW Ultrabell simply because having the extra two bolts in there provides an even stronger joint between the bellhousing and case, but we've used JW bellhousings on 6-bolt cases without any problems as well.

We have not found any significant power limitations (within reason) to the 6-bolt TH400 transmission case. We have a customer with a 3,000 pound drag radial car equipped with an alcohol EFI 632 and an F-3R 136 ProCharger utilizing a 6-bolt TH400 case without any issues. Another customer of ours runs a 6-bolt case behind his 498 DRCE II combination that turns upwards of 10,200 RPM, and, again, has had no issues.

We do prefer to use an 8-bolt case when we're building a unit for use with a JW Ultrabell simply because having the extra two bolts in there provides an even stronger joint between the bellhousing and case, but we've used JW bellhousings on 6-bolt cases without any problems as well.

Thanks for the info. I have a 78 Malibu that weighs 3600 lbs with the driver .Its got a F1a ProCharged 468 Big-Block . Stepping up to a TH-400 & a 9''rearend so I can turn up the boost. I was curious about the case because I had never heard of people shying away from the 6 bolt cases. The car goes 10.02 now with a TH350 & a 8.5 GN rearend but the trans let go at the end of the season so Im doing it all at once so im not cutting the driveshaft more than once. I run Radial -Pros & will be using a trans-brake.

Thanks for the info. I have a 78 Malibu that weighs 3600 lbs with the driver .Its got a F1a ProCharged 468 Big-Block . Stepping up to a TH-400 & a 9''rearend so I can turn up the boost. I was curious about the case because I had never heard of people shying away from the 6 bolt cases. The car goes 10.02 now with a TH350 & a 8.5 GN rearend but the trans let go at the end of the season so Im doing it all at once so im not cutting the driveshaft more than once. I run Radial -Pros & will be using a trans-brake.

No issues at all with a 6-bolt case in that combination. You have nothing to fear. Whoever is telling you to avoid that case is providing incorrect information.

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